Building an 8-foot wind turbineBrent SummervilleAppalachian State University

Research: In search of Plans

• Backhome Magazine article www.backhomemagazine.com

• www.otherpower.com

• …derived from Hugh Piggott’s axial flux plans or “How to build a wind turbine”

• Go with the source and follow plans closely

Research: Hugh Piggott

Workshops in Washington, Scoraig, CAT, Edinburgh, Ghana, France, Costa Rica, Liverpool…..

This is Jay from France. He also came to a Beech Mountain workshop.

Resources: Woods Lab• Sat in on Intro to Wood

Technology • Trained on techniques, tools,

machinery and safety• Practice…Sanding block,

cedar tool box• Last semester for Bill Hanner

•Draw knife•Hand plane•Spoke shave•Lathe•Jointer•Sanders•Gluing panels•Planer•Bandsaw•Drill press•Table saw…

Resources: Metals Lab

• Sat in on Intro class• Trained on techniques, tools,

and machinery• Copper nameplate, dinner

bell, apple butter stand• Nice working with Leo and

Dave•Welding•Mill•Lathe•Plasma torch•Blacksmithing•Grinding•Tapping•Sheet metal fab•Drill press•Iron worker…

Bladecarving

Basswood with termites Thickness, width, length Layout

Carve with draw knife and spoke shave

Sand, sand, sand Check, carve, sand…

Jointer, planer, table saw, and belt sander to form 1-1/2”x6”x52” blanks

Finished length is 48”. Keep long until finished carving. Makes for a nice blade tip.

Start with a precise layout

Simple tools

Carve the taper with the drawknife

Clamp and sand to keep the blades

matched

Carve the twist and check the drop

The drawknife can remove a lot of material quickly, and it’s a good workout

Carve the thickness

The spoke shave is pleasant to work with

Carve the airfoil, keep watch on the

30% line

Bladecarving: Suck not Push

Source: http://www.graphics.cornell.edu/academic/archartpcg/spring01/students/rr63/ROA/windworks01.jpg

Cut to length, cut the 120o angles, ready for the rotor hub

Layout holes for wood screws and studs

Drill the through holes for the ½”

studs square to the hub

Sanding the hub on the lathe

Assemble the rotor, keep the tip-to-tip distance within ½”

After painting and re-assembly, tip-to-tip was 84”, 84-1/8”, 84-1/4”

Decided to skip the wedges

Axial Flux Alternator: Stator

Wind coils Build a mold and layout coils Solder a 3-phase star

Cast in polyester resin Cleanup casting Drill and mount

Keep em’ tight so they will fit into the mold

Clamp coils in position for soldering

Strip with knife, solder, shrink tubing

Build a mold

Fiberglass cloth for strength

Mold release

Place the coils, position the three output wires in conduit, pour in polyester resin and cloth, clamp and cure

Free the stator and clean it up

Axial Flux Alternator: Rotors

Buy laser-cut plates, machine the holes

Careful with those Neo magnets! Position magnets with a jig

Cast in polyester resin No screws needed Clean up and be careful

Flat, not flat

My attempt at a rotor plate is on the right. Laser cut plate on the left.

Superglue magnets to plate to avoid movement

during casting

An index hole in every plate keeps things aligned

Build a mold

Do all three castings together and do it outside (strong smell)

Cast in Polyester resin with fiberglass cloth

Checking the alternating polarity

Stator and rotors, minimal

air gap

Axial Flux Alternator: Magic

Most of the electric power in the world is 3 phase.  The concept was originally conceived by Nikola Tesla and

was proven that 3 phase was far superior to single phase power.  3 phase power is typically 150% more

efficient than single phase in the same power range.  In a single phase unit the power falls to zero three times during each cycle, in 3 phase it never drops to zero.  The power delivered to the load is the same at any

instant.   Also, in 3 phase the conductors need only be 75% the size of conductors for single phase for the

same power output. source: www.windstuffnow.com/ main/3_phase_basics.htm

An electrically charged particle moving in a magnetic field will experience a force

(known as the Lorentz force) pushing it in a direction perpendicular to the magnetic

field and the direction of motion: Source:

http://www.wondermagnet.com/magfaq.html#q18

Rectified to DC(one phase shown)

Fabricate the Alternator Mount

Salvage steel Visit a junkyard Prep steel, fabricate

Make strong welds Machine holes Clean, prime, paint

Plasma torch…upping the embodied energy

The angle grinder cleans up ugly welds

The type disc with flexible

sanding flaps works nicely for

finishing and smoothing

Fabricate the Tail

Vintage Jacobs whale tail

My version

Cool ideas

Assembly

• Too much time in Kerr Scott

• Moved the operation home for final assembly

• Wife and dogs were happy

• Stand borrowed from Whisper 200 demo

Assembly: Tower adapter

Assembly: Alternator Bracket

Assembly: Hub

Assembly: Back Rotor

Assembly: Stator

Assembly: Front Rotor and J-Box

Assembly: Tail

Assembly: Ready for Blades

Costs

• Minimum for a new 1kW turbine is about $1700

• My cost = $836

Description Source Total(24) Neodymium Iron Boron (NdFeB) magnets Forcefield 156.00$ (2) 6-lb spools of #15 AWG magnet wire Forcefield 110.00$ (2) 35 amp bridge rectifiers Forcefield 11.00$ Shipping Forcefield 23.60$ Basswood for blades Tech Dept 50.00$ Chevrolet Cavalier rear wheel hub T&T Auto Salvage 30.00$ Fiberglass cloth Walmart 7.88$ Wax polish Walmart 1.88$ Super glue Walmart 1.47$ Bondo polyester resin NAPA 47.60$ SS fasteners and spray paint New River 40.86$ 2-3/4" hole saw Lowes 17.47$ Drill bit set Lowes 17.64$ 1/2" Plywood Lowes 4.15$ 3" hole saw Lowes 13.66$ Plugs Lowes 1.98$ White box cover Lowes 0.98$ White exterior house paint Lowes 8.97$ White primer Lowes 10.27$ 1-1/4" pipe Lowes 12.64$ Paint brush Lowes 8.47$ Grinder disc - resin Lowes 2.97$ Grinder disc - sanding Lowes 7.47$ 3/8" plywood Lowes 17.75$ 3/4" plywood Lowes 10.98$ Steel and SS threaded rod Triplett & Coffey 220.00$

Total 835.69$

Conclusion

• Well done plans• Slight customization

– No wedges– Wiring details– Nose cone

• Lots of work• Use of magic

– Lift– Electricity

• Economical• To do next: controller and

tower

Questions?